<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>案例-导航</title>
    <style>
        div {
            width: 100%;
        }

        ul {
            font-size: 30px;
            list-style: none;
            display: flex;
        }

        .li1 {
            font-weight: 600;
        }

        li {
            margin-right: 30px;
        }

        .li2 {
            transition: width 0.5s, height 0.5s;
        }

        li:hover {
            color: rgb(247, 186, 17);
            border-bottom: 4px solid rgb(247, 186, 17);
        }
    </style>
</head>

<body>
    <div>
        <ul>
            <li class="li1">首页</li>
            <li class="li2">热门美食</li>
            <li>特色小吃</li>
            <li>甜品推荐</li>
        </ul>
    </div>
</body>

</html>